Compass Barrel Cactus
Scientific Name: Ferocactus cylindraceus (Engelm.) Orcutt
Synonym: Echinocactus acanthodes, Echinocactus rostii, Ferocactus acanthodes
var. rostii, Ferocactus rostii, Echinocactus acanthodes var. rostii, Ferocactus
acanthodes, Echinocactus cylindraceus, Echinocactus viridescens var.
cylindraceus, Thelocactus hertrichii, Echinocactus hertrichii
A Compass Barrel Cactus blooming around May-June Recommended Temperature Zone:
Frost Tolerance: Hardy to 20° F. (-7°C)
Minimum Avg. Temperature: 50°F (10°C)
Sun Exposure: Needs full sun
Origin: Southwest USA(Arizona, California), northern Mexico (Sonora, Baja
California) at 2000 to 5000 feet elevation (600-1500 m)
Growth Habits: Solitary, grows slowly to 8 feet tall (2.4 m), 14 inches in
diameter (35 cm); 18 to 25 obtuse ribs; Areoles are 0.6 to 0.8 inches apart (1.5
to 2 cm); 1 to 4 central spines, generally 2 are longer, one upper and one
lower, curved but not hooked, 3 to 4.5 inches long (7.5-11 cm); 6 to 12 white
spreading radial spines, 0.8 to 1.6 inches (2-4 cm).
Watering Needs: Little water in a moderately rich, well drained soil. Ferocacti
die easily with too much water or not enough sun.
This cactus was known for years as Ferocactus acanthodes, until the name was
found invalid. The valid name is now F. cylindraceus.
The Compass Barrel Cactus grows slanted in the direction of the south. This is
due to the fact that the northern side in the cactus, somewhat protected from
the sun grows faster than the south side. The picture is taken from the south
The different varieties are distinguished by the shape and color of the spines,
although the spine color can vary widely within the same population.
Ferocactus cylindraceus needs little water in a moderately rich, well drained
soil. Ferocacti die easily with too much water or not enough sun. They come from
an area that receives winter rain, so some limited rain in early spring is fine,
but in habitat, the soil around them is bone dry most of the year.
The Compass Barrel has yellow or orange flowers in may through August, 1.6 to 2
cm (4-5 cm).